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<title>Berkeley DB Reference Guide: Release 4.2: Client replication environments</title>
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<td><b><dl><dt>Berkeley DB Reference Guide:<dd>Upgrading Berkeley DB Applications</dl></b></td>
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<p align=center><b>Release 4.2: Client replication environments</b></p>
<p>In previous Berkeley DB releases, replication clients always behaved as if
<a href="../../api_c/env_set_flags.html#DB_TXN_NOSYNC">DB_TXN_NOSYNC</a> behavior was configured, that is, clients would
not write or synchronously flush their log when receiving a transaction
commit or prepare message.  However, applications needing a high level
of transactional guarantee may need a write and synchronous flush on
the client.  By default in the Berkeley DB 4.2 release, client database
environments write and synchronously flush their logs when receiving a
transaction commit or prepare message.  Applications not needing such
a high level of transactional guarantee should use the environment's
<a href="../../api_c/env_set_flags.html#DB_TXN_NOSYNC">DB_TXN_NOSYNC</a> flag to configure their client database
environments to not do the write or flush on transaction commit, as this
will increase their performance.  Regardless of the setting of the
<a href="../../api_c/env_set_flags.html#DB_TXN_NOSYNC">DB_TXN_NOSYNC</a> flag, clients will always write and flush on
transaction prepare.</p>
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